A known procedure for hair transplants, called graft harvesting, involves surgically removing strips of scalp containing many hair follicles. The strip is then cut into smaller pieces each containing one or more hair follicles and used as grafts in scalp areas devoid of hair. The known procedure uses a double- or trip-bladed knife as a scalpel with which the surgeon makes simultaneously two, respectively three, parallel shallow incisions which must be parallel with the hair shafts and should avoid, i.e., cuts around, usable hair shafts. Ideally, the incisions should be to the same depth. These constraints require that the blades remain parallel with the hair throughout the cutting procedure, and that the cutting pressure applied to the scalpel by the surgeon results in substantially equal pressures at the multiple blade cutting edges. If properly done, the strip of hair with all hair follicles preserved an be readily removed, divided into individual graft sizes, and replaced in bare scalp areas. The surrounding hair covers the narrow scalped strip.
Problems encountered in implementing the above procedure include: maintaining even cutting pressures on the multiple blades, maintaining the blades parallel, controlling the blade spacings and lengths to match the varying scalp contour and hair follicle arrangement of particular patients to maximize the graft harvest, and avoiding the generation of excessive heat which might damage the hair follicles.